Ten years ago this month, erectile dysfunction -- a once-whispered-about disorder -- did more than just come out of the closet. ED, as it's now known, began strutting across America's television screens.

Bob Dole started talking. Then the grandfatherly former senator stepped aside and NASCAR drivers took over. Then a middle-aged garage band soon crooned, "Viva Viagra!"

The U.S. Food and Drug Administration approved the Pfizer-made drug Viagra in March 1998 to treat erectile dysfunction, a disorder gussied up with a new name (impotence was out) and a sophisticated advertising campaign. An extremely private matter suddenly seemed everywhere.

Since then, more than 35 million men worldwide have taken the drug. Viagra has spawned a new class of drugs, greater insight into men's health, an effort to find similar drugs for women -- and, yes, a rash of Jay Leno jokes.

To some, Viagra has started nothing less than a second sexual revolution. The massive effort to sell the drug knocked down barriers to talking about a once-taboo subject: sex and aging.

"These drugs have been the gateway to allow patients to have open communication with doctors and their partners about sexuality," said Terrie Ginsberg, a physician at the New Jersey Institute for Successful Aging. "Doctors have opened up, too. These drugs have helped us explore the myth that people over 50 are not sexual."

Physicians say the value for patients cannot be overestimated. Many men with prostate cancer discovered they could enjoy sex again. So did many, but not all, men with diabetes or cardiovascular disease.

"Before these drugs, all we had was a vacuum pump, surgery or herbal things that didn't work," said Stuart Shoengold, chairman of the urology department at Newark (N.J.) Beth Israel Medical Center. "So most men lived with the situation. It was hard for primary-care physicians even to talk about erectile dysfunction because they had nothing to offer."

(On the negative side, some older women began to complain that, with Viagra, their husbands had become much more interested in sex than they were.)

How it was developed

The blockbuster drug -- $1.7 billion in sales last year -- was not one that Pfizer ever set out to create. In the 1980s, Pfizer scientists in Sandwich, a small town on England's southeastern coast, theorized that blocking an enzyme called PDE5 could expand blood vessels and treat angina caused by reduced blood flow to the heart.

They began testing the drug on volunteers in the 1990s. But the drug had a short life and volunteers needed to take the medication three times each day, causing side effects such as muscle aches. Yet men also began reporting another side effect: unexpected erections.

Pfizer switched tracks. The company began testing the drug specifically on men with erectile dysfunction.

"The results were quite amazing," said Peter Ellis, a Pfizer scientist who worked on the drug's development. At the end of the study, many volunteers did not want to return unused pills. Ellis recalls a letter from a 44-year-old man with Parkinson's disease who said he could once again make love to his wife.

"It was like throwing a drowning man a life preserver and then pulling it back," Ellis recalled. "But feedback like this made us think we needed to provide this drug to people who needed it."

More than 10 years after the PDE5 inhibitor project began, Pfizer asked the U.S. Food and Drug Administration and other regulatory agencies around the globe to let the company sell the drug, marketed as Viagra.

New view of dysfunction

Viagra and two similar drugs that followed, Cialis by Eli Lilly & Co. and Levitra by Schering-Plough, have changed the way physicians and psychologists treat, and even view, sexual dysfunction.

"The drugs have ushered in an era of looking at sexual problems from a medical perspective instead of from a psychological perspective," said Margaret Nichols, a sex therapist and founder of the Institute for Personal Growth, a mental health organization.
Nichols said she still treats men with erectile dysfunction, which can be complicated by psychological issues. "We see the more complicated cases ... But for a lot of men, whatever psychological issues they have can be overridden with Viagra," Nichols said.

Pfizer scientists said their research showed that erectile dysfunction -- like the canary in the coal mine -- is often an early indication of other health problems, such as diabetes, hypertension, high cholesterol or cardiovascular disease.

"ED can be a warning sign. This was not really known but is now established and accepted," said Teresa Griesing, senior medical director of Pfizer's Global Viagra team. For instance, Pfizer cited one study that found 64 percent of men hospitalized for heart attack experienced prior erectile dysfunction.

Changes for women

The changes sparked by Viagra have spilled into women's health. Nichols, the sex therapist, said psychologists now are more likely to look at women's sexual dysfunction, such as painful intercourse or low sex drive, from a medical viewpoint and not simply assume the women are experiencing psychological distress.

Pharmaceutical companies are searching for the female equivalent of Viagra to treat female sexual dysfunction, or FSD, but treating women appears far more complex. Pfizer tested Viagra on women and abandoned the effort. Hormonal patches, some containing testosterone, have failed to gain FDA approval for treatment of female sexual dysfunction.

Yet drug companies continue research, spurred on by estimates that the market for treating female sexual dysfunction could reach $5 billion in the United States alone.